The program is directed at structural studies of macromolecules from high resolution data on proteins in the form of single crystals to the larger scale geometry presently assessable in organelles such as ribosomes and plasma membranes. The techniques to be employed center on diffraction and solution scattering of both X-rays and neutrons. In addition to the time-average structures, which are the most immediate output of such work, the program will be particularly aimed at studying the motion of various parts of the polymer chains and of subunits with respect to each other in the larger aggregates. Motion can, in part, be inferred from static structural differences under varied conditions of environment and ligation. Of special interest is the motion of specific side chains during catalytic cycles, of the polymerase class of enzymes along the nucleic acid chains, and the translocation step of ribosomes on the message during protein synthesis. The control of these processes by specific ligands will be investigated. The studies will combine both experimental and theoretical approaches to these problems.